Centering device for artificial dentures



March 20, 1956 w. c. GREEN CENTERING DEVICE FOR ARTIFICIAL DENTURES Filed June 18, 1954 FIG-8 so 30 37 33 Rm wE N R EG V C N J T R E 8 l W ATTORNEYS United States Patent CENTERING DEVICE FOR ARTIFICIAL DENTURES Wilbert C. Green, Dayton, Ohio Application June 18, 1954, Serial No. 437,617

6 Claims. (Cl. 32-19) This invention relates to an instrumentfor use in the manufacture of artificial dentures.

The invention has special relation to an instrument of this character for employment by the dentist for the purpose of determining the proper vertical relation in an articulator of the models of the patients jaws on which the artificial dentures are to be constructed. More particularly, the invention is directed to the elimination of guesswork with respect to this vertical relationship by establishing a positively indexed relation of such jaw models with respect to the true centric position for the particular patient. i

It is a primary object of the present invention to provide an instrument of the above character which is of such construction that the operating parts thereof, together with bite blocks carried thereby, may be releasably secured together in positively indexed relation with respect to centric such that the instrument and the bite blocks can be transferred to an articulator with the assurance that the true centric relationship of the patients jaws will be reproduced in the articulator and the dentures constructed thereon.

Another object of the invention is to provide such an instrument which operates in part by tracing or otherwise scribing a Gothic arch pattern indicating the centric position for the patient and in which such Gothic arch pattern is reproduced entirely externally of the patients mouth for ready viewing by the dentist as it is produced.

It is also an object of the invention to provide an instrument of the above character which accurately reflects variations in the hardness of the patients mouth in addition to establishing the centric position of the jaws.

Other objects and advantages of the invention will be apparent from the following description, the accompanying drawing and the appended claims.

In the drawing- Fig. 1 is a somewhat diagrammatic view taken generally in vertical section through the mouth of the patient and showing the instrument of the invention in operative position in the mouth;

Fig. 2 is a view of the underside of the top plate forming one of the main parts of the instrument of Fig. 1;

Fig. 3 is a view of the upper surface of the lower plate forming the other main part of the instrument of Fig. 1;

Fig. 4 is a view similar to Fig. 1 showing the instrument of the invention mounted in combination with jaw models in an articulator;

Fig. 5 is a fragmentary top view of the instrument of Figs. l-4 showing the arrangement for retaining the main parts together prior to use thereof;

Fig. 6 is an enlarged fragmentary section on the line 66 of Fig. 5;

Fig. 7 is an enlarged fragmentary section on the line 7-7 of Fig. 2; and v Fig. 8 is an enlarged fragmentary section on the line 8--8 of Fig. 3.

Referring to the drawing, which illustrates a preferred embodiment of the invention, the instrument of the invention comprises essentially a pair of upper and lower plates 10 and 11 and the cooperating parts carried thereby. The upper plate 10 is proportioned to be received within the patients mouth and includes an elongated arm 12 of adequate length to extend a substantial distance outwardly of the mouth as shown in Fig. 1. As an illustrative example of proportions found satisfactory in the practice of the invention, this upper plate and arm may be formed of l6-gauge stainless steel with an overall length of the order of four inches, and other suitable non-corroding materials may also be used, such as aluminum and the like, if of adequate stiffness. At its outer end, the arm 12 carries a scribing unit including a pin 13 mounted in a threaded bushing 14 and spring-biased downwardly by means of a coil spring 15 and split ring collar 16. The bushing 14 is adjustably mounted by means of a lock nut 17 in a threaded hole 18 adjacent the outer end of arm 12.

The lower plate 11 is generally similar in configuration to the upper plate It) and also includes an arm 20 adapted to extend outwardly of the patients mouth. At its outer end, the arm 20 is widened to provide a table portion 22 underlying the scriber 13, and the arm 20 is also formed as shown in Fig. 1 to locate the table 22 in downwardly offset relation with the plate 11 to provide for adequate viewing of the surface of the table by the dentist. The sides of the table 22 are provided with upwardly extending side walls 23 facilitating the mounting on the table of a temporary record sheet or tracing sheet 25 of suitably soft material such as soft metal or plastic.

The lower plate 11 is slotted as shown in Fig. 3 to form a centrally disposed tongue portion 30 connected with the remainder of the plate by a relatively narrow strip 31. This tongue 30 is provided with a plurality of springbiased bearings 33, three being shown, arranged symmetrically thereon in upwardly projecting relation for engagement with the under surface of the plate 10. As shown in Fig. 8, each of these hearings forms the head of a plunger 34 mounted within a cup shaped bushing 35 and provided with a biasing spring 36. The several bushings 35 are threaded through the tongue 30, and they are shown as provided with hexagonal portions 37 facilitating threading movement thereof. These bearings 33 provide for adjustment of the plates 10 and 11 into such non-parallel relationship as may be occasioned by variations in the hard ness of the patients month during use of the device. The portion 31 of the tongue 30 provides additional resilience between the two plates for use with a patient having an unusually hard mouth where the plungers 33 are depressed to substantially the limit provided therefor in the bushings 35.

Referring to Fig. 4, the upper plate 11 carries an upper bite block 4% of the usual type formed by the dentist from a plaster model cast from an impression of the mouth in the usual Way, and the lower plate 11 carries the corresponding lower bite block 41. reference character 42 designates the ridge in the patients upper jaw from which the upper teeth originally projected, and the corresponding lower ridge is indicated at 43. The bite block 49 is temporarily secured to the upper plate 10 by means of wax 44, and the corresponding wax for the lower bite block and plate 11 is indicated at 45. These wax sections 44 and 45 are proportioned by the dentist in accordance with the shape of the patients mouth to locate these parts in such manner that the adjacent surfaces of the plates 1! and 11 will bear the same spatial relation to each other which the artificial teeth of the patient should bear in their finished in Fig. 1, the

If this sheetis ofsoft metal such as lead or the like, it is fixed on the table by means such as press fitting between the side walls 23 or by turning down tab portions thereon over the edges of the table 22. It has been found especially convenient to form such record sheet of a resin such as methyl methacrylate, with a film of the resin being cast directly on the table 22 or adhered thereto as a preformed sheet. The record sheet 25 should in any event be of appreciable thickness capable of having a hole formed therein for receiving the point of the scribing pin 13, satisfactory results having been obtained with a resin sheet of a thickness of the order of 0.20 inch.

After the record sheet 25 is properly in place, the instrument is assembled in the patients mouth as shown in Fig. l. The patient then closes his jaws and moves his lower jaw horizontally back and forth between its positions of extreme protrusion, extreme rctrusion and extreme left and right lateral movements. This action causes the scribing pin 13 to trace the desired Gothic arch pattern upon the record sheet 25, as indicated at in Fig. 3. Such pattern may be scribed directly in the surface of the sheet 25 if it is of sufiiciently soft material, or the surface of the sheet may be coated with ink or dye if desired.

After the Gothic arch pattern 50 has thus been scribed,

the dentist temporarily removes the instrument from the patients mouth and drills a small hole 51 in the sheet 25 at the apex of the arch pattern, this being the point of true centric relationship of the patients jaws. The instrument is then again assembled in the patients mouth, the point of the pin 13 is inserted in the hole 51 to index the upper and lower plates together, and the patient is instructed to bite with his jaws in centric relation. It will be apparent that with the scribing parts of the instrument clearly visible outside the mouth during this operation, the dentist is readily able to guide the patients jaws to their centric position if necessary, and he can thus thoroughly establish that the jaws are properly in their centric relation before proceeding further.

, During this biting step, if there are variations in the hardness of the patients mouth, which is a frequent occurrence, they will cause the plates 1i) and 11 to move into nonparallel relationship against the springs 36 providing the biasing force for the several bearings 33 as described. In other words, if the mouth is of uniform hardness, the bearings 33 will be uniformly depressed as the jaws close, but if there are soft spots in the mouth, the several bearings wiil be nonuniformly depressed.

When the dentist is satisfied that the bite relationship of the patients jaws has been properly established by the relative positioning of the plates It) and 11 while indexed in centric relation by the pin f3 and hole 5E, he secures the plates together in this established relationship by introducing small amounts of quick setting plaster between the plates, as indicated at 55 in Fig. 4. if the two plates are of a matte finish metal, this will ordinarily give adequate adhesion without special provision. it may be desirable, however, to roughen the opposed surfaces of plates 10 and 11, especially if they are made of polished metal, as indicated by the grooves 66 and 61 in Figs. 2 and 3. With these grooves in a definite pattern as shown, they will also serve to index the plates with respect to each other and the plaster $5 in the event that the two plates should accidentally come apart before they are properly mounted in the articulator. A similar groove pattern may also be provided on the other surfaces of the plates 10 and 11 for similarly aiding the adhesion and indexing of the plates to the bite blocks.

Grooves are also provided in the surfaces of the plates 10 and 11 which face their associated bite blocks, as indicated at 62. and 63 in Figs. 5 and 6, to aid their adhesion to the bite blocks, and. these grooves may be in a pattern as described for ready indexing in the event of accidental separation of a plate from its associated bite block. in addition, these grooves may be used in conjunction with a pair of O-shaped clips 65 to hold the plates 14) and 11 together both when the instrument is not in use and also during initial adhering of the plates to the bite blocks. As shown in Figs. 5 and 6, these clips fit in parallel grooves 62 and 63 to hold the plates together against the spring-biased plungers 33.

After the instrument has thus been secured in the proper position, it is removed from the patients mouth and transferred to a suitable articulator. Referring to Fig. 7, the upper and lower arms of a conventional articulator are indicated at and 81. On the lower arm 81 is rigidly mounted the cast model 82 of the patients lower jaw. The cast model 83 of the upper jaw, however, is initially separate from the upper arm 80 and instead is mounted on the upper bite block it Since the bite blocks have already been secured in the proper centric relationship as described, this automatically aligns the model 83 in centric relationship with the model 87., and While the parts are held in this positio the model 83 is rigidly secured to the arm 86, as by applying to the top thereof sufficient quick setting plaster 85 to fill the hollow center portion of arm 80.

This completes the use of the instrument, since the centric relationship of the models 82 and 83 has thus been established in the articulator. The instrument can therefore then be removed, cleaned and sterilized for subsequent use, and the dentist proceeds in the usual way to construct the artificial dentures on the models in the articulator. When the instrument is to be used again, the record sheet 25 is replaced, or if this sheet 25 is of resin, it can be reused after filling the hole 51 with sufficient additional resin and smoothing of its outer surface.

While the form of device herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of device, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. An instrument for use in the manufacture of artificial dentures to establish and record the centric position of the patients jaws, comprising an upper plate formed for insertion in the patients mouth in supporting relation with an upper bite block, a lower plate formed for insertion in the patients mouth in supporting relation with a lower bite block, an arm on one of said plates proportioned to project outwardly from the patients mouth, scribing means carried by said arm, another arm on the other of said plates proportioned to project out wardly from the patients mouth and including a table portion vertically aligned with said scribing means for scribing thereon of a Gothic arch by said scribing means, means on said table portion for defining an indexing hole for said scribing means at the apex of said arch, a plurality of spring-biased bearing members mounted on one of said plates, means forming a cooperating bearing surface on the other said plate for engagement by said bearing members to provide for non-parallel adjustment of said plates under biting pressure in accordance with variations in the hardness of the patients mouth with said scribing means indexed in said hole, and said plates having portions thereon in facing relation for receiving adhesive material to secure said plates together for transfer to an articulator in such non-parallel adjustment and with said scribing means indexed at the apex of such Gothic arch.

2. An instrument for use in the manufacture of artificial dentures to establish and record the centric position of the patients jaws, comprising an upper plate formed for insertion in the patients mouth in supporting relation with an upper bite block, an upper arm on said upper plate proportioned to project outwardly of the mouth, a lower plate formed for insertion in the patients mouth in supporting relation with a lower bite block, a lower arm on said lower plate proportioned to project outwardly of the mouth in underlying relation with said upper arm, means on one of said arms for scribing a Gothic arch,

means on the other said arm for supporting a temporary record sheet of appreciable thickness for scribing of said Gothic arch thereon and forming therein of an indexing hole for said scribing means at the apex of said arch, a plurality of spring-biased bearing members mounted on one of said plates for engagement by the other said plate to provide for non-parallel adjustment of said plates under biting pressure in accordance with variations in the hardness of the patients mouth, and said plates having portions thereon in facing relation for receiving adhesive material to secure said plates together for transfer to an articulator in such non-parallel adjustment and with said scribing means indexed at the apex of such Gothic arch.

3. A device for use in the manufacture of artificial dentures to establish and record the centric position of the patients jaws, comprising an upper plate formed for insertion in the patients mouth in supporting relation with an upper bite block, a relatively narrow upper arm on said upper plate proportioned to project outwardly of the mouth, a scribing member depending from said upper arm, a lower plate formed for insertion in the patients mouth in supporting relation with a lower bite block, a lower arm on said lower plate proportioned to project outwardly of the mouth in underlying relation with said upper arm, said lower arm including a fiat portion of substantial width for cooperation with said scribing member to effect scribing thereon of a Gothic arch, said fiat portion being arranged in downwardly offset relation with said lower plate to provide for viewing by the operator of the scribing of such arch, a temporary record sheet on said flat arm portion for directly receiving such scribed arch and being of appreciable thickness for formation therein of a locating hole at the apex of such arch to receive and index said scribing means, and said plates having portions thereon in facing relation for receiving adhesive material to secure said plates together for transfer to an articulator with said scribing means indexed in such hole in said record sheet.

4. An instrument for use in the manufacture of artificial dentures to establish and record the centric position of the patients jaws, comprising an upper plate formed for insertion in the patients mouth in supporting relation with an upper bite block, a relatively narrow upper arm on said upper plate proportioned to project outwardly of the mouth, a scribing member depending from said upper arm, a lower plate formed for insertion in the patients mouth in supporting relation with a lower bite block, a lower arm on said lower plate proportioned to project outwardly of the mouth in underlying relation with said upper arm, said lower arm including a flat portion of substantial width for cooperation with said scribing member to eifect scribing thereon of a Gothic arch and arranged in downwardly offset relation with said lower plate to provide for viewing by the operator of the scribing of such arch, a temporary record sheet on said flat arm portion for directly receiving such scribed arch, said record sheet being of appreciable thickness providing for formation therein of a locating hole at the apex of such scribed arch to receive and index said scribing means, at least three spring-biased bearing members mounted on one of said plates for engagement by the other said plate to provide for non-parallel adjustment of said plates under biting pressure in accordance with variations in the hardness of the patients mouth, and said plates having portions thereon in facing relation for receiving adhesive material to secure-said plates together for transfer to an articulator in such non-parallel adjustment and with said scribing means located in indexed relation in such hole in said record sheet.

5. An instrument for use in the manufacture of artificial dentures to establish and record the centric position of the patients jaws, comprising an upper plate formed for insertion in the patients mouth in supporting relation with an upper bite block, an upper arm on said upper plate proportioned to project outwardly of the mouth, a lower plate formed for insertion in the patients mouth in supporting relation with a lower bite block, a lower arm on said lower plate proportioned to project outwardly of the mouth in underlying relation with said upper arm, said lower plate including a centrally disposed tongue portion having an integral resilient connection with the remainder of said plate to provide for depression of said tongue out of the plane of the remainder of said lower plate, bearing means carried by said tongue for engagement with said upper plate to provide for nonparallel adjustment of said plates by resilient depression of said tongue on the biting pressure in accordance with variations in the hardness of the patients mouth, means on one of said arms for scribing a Gothic arch on the other of said arms, means on said other arm for indexing said scribing means at the apex of such Gothic arch, and said plates having portions thereon in facing relation for receiving adhesive material to secure said plates together for transfer to an articulator in such non-parallel adjustment and with said scribing means indexed at the apex of such Gothic arch.

6. An instrument for use in the manufacture of artificial dentures to establish and record the centric position of the patients jaws, comprising an upper plate formed for insertion in the patients mouth in supporting relation with an upper bite block, an upper arm on said upper plate proportioned to project outwardly of the mouth, a lower plate formed for insertion in the patients mouth in supporting relation with a lower bite block, a lower arm on said lower plate proportioned to project outwardly of the mouth in underlying relation with said upper arm, said lower plate including a centrally disposed tongue portion having an integral resilient connection with the remainder of said plate to provide for depression of said tongue out of the plane of the remainder of said lower plate, a plurality of spring-biased bearing members mounted on said tongue to provide for non-parallel adjustment of said plates by the bite pressure in accordance with variations in the hardness of the patients mouth and with said tongue being resiliently depressible out of the plane of the remainder of said lower plate under extreme biting pressures, means on one of said arms for scribing a Gothic arch on the other of said arms, means on said other arm for indexing said scribing means at the apex of such Gothic arch, and said plates having portions thereon in facing relation for receiving adhesive material to secure said plates together for transfer to an articulator in such non-parallel adjustment and with said scribing means indexed at the apex of such Gothic arch.

References Cited in the file of this patent UNITED STATES PATENTS 2,562,106 Leathers July 24, 1951 

